The invention relates generally to a deburring tool for removing burrs from the circumferential edge of a borehole, and more particularly, to a deburring tool having a replaceable cutting insert.
Prior to the present invention, various special tools have been disclosed for removing burrs from the circumferential edge surrounding openings of passages and for adding chamfers thereon. Examples of such tools are disclosed in U.S. Pat. Nos. 5,358,363 and 5,501,554 which are entitled Deburring Tool and issued Oct. 25, 1994 and Mar. 26, 1996, respectively, to William A. Robinson, the inventor of the present invention. These U.S. Patents are incorporated by reference.
The deburring tool shown in the ""363 patent generally includes an elongated cylindrical arbor formed with a cutting blade recess. A unitary cutting tool is received in the recess and includes a cutting head with an integral, elongated, flat, resilient blade extending therefrom. The blade is mounted in the arbor by a pair of axially spaced pins, at least one of which, the pivot pin, extends through a hole in the blade to define a pivot point about which the blade can flex. The other pin engages the end of the blade opposite the cutting head and holds this end in a fixed relationship with respect to the arbor, such that the cutting head projects from the recess to engage a workpiece. The cutting head is thereby resiliently yieldable to permit the cutting head to move inwardly with respect to the recess during a deburring operation. When the cutting tool becomes worn out or otherwise damaged, the pin securing the blade in a fixed relationship is loosened such that the entire cutting tool may be replaced. Though deburring tools of this type perform quite satisfactorily, a deburring tool having an easily replaceable cutting insert, as opposed to an entire replaceable cutting tool, would be preferable for improved economy and efficiency.
Other examples of deburring tools are disclosed in U.S. Pat. Nos. 5,803,679 issued Sep. 8, 1998 to Ulf H. Heule for a Deburring Tool for Deburring the Edges of Boreholes and U.S. Pat. No. 5,755,538 issued May 26, 1998 to Ulf Heule for a Deburring Tool. While the prior art patents ""679 and ""538 disclose deburring blades in tool holders, they require separate compression springs operating either through a spring plate and a control pin or a spring pocket formed in the blade for radially urging the cutting blade out of a radial blade mounting window.
In contrast to the prior art constructions, the present invention is drawn to a new and improved deburring tool construction of the resilient arm type in which a cutting insert can be readily removed and replaced on the outer end of a resilient arm.
According to the invention, a deburring tool for deburring an opening of a borehole is provided comprising an elongated cylindrical arbor, a mounting pin, a pivot pin, a resilient arm, and a replaceable cutting insert. The elongated cylindrical arbor includes a forward axial end, a rearward axial end, and a longitudinal slot extending between the forward and rearward ends. The mounting pin is inserted into the arbor and is located at an axial position between the forward and rearward ends of the arbor. The pivot pin is inserted into the arbor and is located at an axial position between the forward end of the arbor and the mounting pin. The resilient arm is received in the longitudinal slot and includes a terminal end for coupling the resilient arm to the arbor via the mounting pin, an attachment end, and a pivot recess for allowing the resilient arm to flex about the pivot pin. Lastly, the replaceable cutting insert includes a forward cutting edge and an attachment recess for receiving the attachment end of the resilient arm. The replaceable cutting insert radially extends out of the longitudinal slot when the deburring tool is not engaging the borehole and the replaceable cutting insert radially retracts within the longitudinal slot when the deburring tool is engaging the borehole.
According to another aspect of the invention, a method for replacing a cutting insert of a deburring tool is provided and includes the following steps. (a) providing a deburring tool which includes an elongated cylindrical arbor, a pivot pin including a first locking feature, a resilient arm including a pivot recess with a second locking feature, and a cutting insert attached to the resilient arm. (b) adjusting at least one of the first and second locking features such that the resilient arm becomes unattached from the pivot pin. (c) extending the unattached resilient arm and the cutting insert out of the arbor. And, (d) replacing the cutting insert.
The deburring tool of the present invention having a replaceable cutting insert has several advantages over the prior art deburring tools. Firstly, the resilient arm flexes around the pivot pin according to the amount of pressure being exerted by a borehole, thus providing a simple, effective, and robust tool capable of deburring openings of a borehole. Secondly, the replaceable nature of the cutting insert allows just the cutting insert to be replaced when it becomes worn out, thus avoiding the unnecessary disposal of other components.